Handheld devices are increasingly being used to manipulate larger and larger data files. For instance, Internet web pages, maps, word processing documents, spreadsheets, and the like are being used more frequently on handheld devices and other devices whose displays are smaller than a conventional desktop monitor. The smaller display size of these devices makes user interaction cumbersome and slow because the user is required to perform lots of scrolling in order to view the complete document; i.e. only a portion of the entire document may be viewed on the smaller display screen at any given time. Additionally, users are more likely to get disoriented within the document because they may forget which subsection of the entire document they are currently viewing.
Similar problems exist on conventional desktop and laptop computers (PCs), although not to the same degree as with handheld devices because the display screen size is typically larger on conventional computers. Several known solutions exist for the above-described problems with respect to conventional desktop and laptop computers. One such solution is the use of scrollbars. That is, when there is more data than can be displayed on a single display screen, scrollbars can be used to move window content up and down or left and right, or both. However, scrollbars are slow and also require precise pointing and interaction by a user. This can interrupt the natural task flow with which the user was previously engaged. In addition, the precision required to scroll on a small-screen device is often difficult to achieve due to the limited size of the display.
Another known solution for conventional PCs is to use a mouse adapted with a roller wheel or trackball, also referred to as a wheel-mouse or trackpoint-mouse. Microsoft® and IBM® mice devices allow scrolling by placing a wheel or a trackball on the mouse. These methods can be inefficient, because the same hand is used for pointing and scrolling, and zooming is not supported. In addition, a wheel-mouse may allow only vertical scrolling, depending on its configuration.
Other known solutions are application specific. That is, many applications allow various levels of zoom control. However, zooming typically takes place in steps, such that there are regular zoom levels. The applications do not smoothly zoom in and out of a document. When these applications zoom in, especially when a big zoom “step” is taken, the user often gets lost because it is difficult to judge where in the document the zooming took place. Zoom stepping is typically performed using a combo-box or complex set of keystrokes (e.g. ctrl +, ctrl −), which also breaks the user's natural task flow.
A known smooth zooming application is Pad++, available on the Internet at the web site http://hci.ucsd.edu/pad++/. However, Pad++ software only allows a user to use one hand for both zooming and panning because it ties zooming and panning operations to a computer mouse. This makes it complex and difficult to master, much less to perform both at the same time. One hand is overloaded with complex functions, while the other hand remains idle.
Thus, it would be an advancement in the art to develop a method and device to overcome the above-described problems in manipulating documents and data files that are larger than the size of a display on a data processing device.